The present invention relates to the transfer of information between two members, one of which is rotatable relative to the other, i.e. across a continuously rotatable interface.
Information, such as control information, needs to be transferred between fixed and rotatable members, for example, the cupola of an armoured fighting vehicle, or other rotating machinery where direct transfer is not possible, such as in radar systems.
Hitherto, electrical slip rings have been used to transfer the information between the two members, but with them are associated the problems of poor contact, unreliability, electromagnetic interference, mechanical complexity, and if the transfer of electrical power is concerned, differences in d.c. (direct current) voltage levels.